Planetary Resources, whose backers include Google's CEO and chairman and director James Cameron, has begun work on satellites it aims to use to spot resource-rich asteroids.

A rendering of satellites that Planetary Resources expects to use to determine… (Planetary Resources )

A group of 21st-century private space entrepreneurs is expected to unveil an ambitious new venture to mine the surface of near-Earth asteroids in search of precious metals and rare metallic elements.

The plan may seem like it was torn from a science fiction novel, and critics say the idea may be far-fetched and difficult for a small company to accomplish. But the company, Planetary Resources Inc., has already drawn an A-list of investors and advisors.

On Tuesday, executives from Planetary Resources are set to announce that work is underway on constructing small satellites, which will be armed with high-powered cameras and sensors to spot resource-rich asteroids as they whiz past Earth.

Within the next decade, the company hopes to use robots to prospect asteroids and gather rare earth materials, which are vital to medical devices, hand-held electronics and computers.

Separately, Planetary Resources of Seattle wants to help NASA astronauts on deep-space missions to Mars.

"Humanity has been driven for thousands of years to explore the Earth for resources," said Peter H. Diamandis, the company's co-founder and co-chairman. "The next step is to expand the economic sphere of humanity beyond Earth's confines."

The sale of extracted precious metals and rare metallic elements to mining companies could one day total billions of dollars, he said. Also, as the availability of these metals increase, the cost will drop for products including defibrillators, hand-held devices, televisions and computer monitors.

On Tuesday afternoon at the Museum of Flight in Seattle, Diamandis is expected to reveal what's ahead for the new company, which now employs some two dozen engineers.

He will make the announcement alongside several of the partners, including commercial space entrepreneur Eric Anderson, former NASA Mars mission manager Chris Lewicki and planetary scientist and veteran NASA astronaut Tom Jones.

"It's a really ambitious project, and sure, they'll have their challenges," said Marco Caceres, senior space analyst for aerospace research firm Teal Group. "But if they are successful and hit a jackpot, it could start a new gold rush."

Diamandis is no stranger to innovative ideas. As chief executive of the nonprofit X Prize Foundation, he helped kick-start the $10-million competition between private companies to develop a manned rocket.

When a team led by maverick Mojave Desert aerospace engineer Burt Rutan pulled off the feat in 2004, the space race among private companies was officially on.

Diamandis, a physician by training, is like many who have invested in the private space field. He's a baby boomer with a zeal for science fiction and a lifelong desire to be an astronaut.

The walls of his Playa Vista office are cluttered with sci-fi photos and memorabilia. Star Trek trinkets are stacked high, along with Yoda toys and Buzz Aldrin-inspired G.I. Joe action figures.

The list of Planetary Resources' business backers is a testament to his ability to tap into well-heeled space enthusiasts who share his love for space travel. However, he won't say how much money the group has invested.

"There are a lot of billionaires out there who want to see the next step in space," Diamandis said.

With declining budgets and the space shuttle program retired, NASA has had to cut exploration programs.

Diamandis believes it's up to private companies to carry the torch in the 21st century.

Within the next two years, the company plans to launch "a swarm" of satellites weighing about 20 pounds and costing as much as $5 million apiece, he said. At distances as high as 500 miles from Earth, the mini-satellites called Arkyd-100s will scour space for potential platinum-rich asteroids.

Data gathered from the satellites will assist in analyzing the composition of an asteroid to determine whether it's worth mining. When they spot one, Planetary Resources will send in a fleet of higher-powered satellites called Arkyd-200s for a closer look. Once they determine it's worth mining, the drilling robots will be sent in.

Diamandis concedes actual mining won't take place for a decade or more. He also said how to retrieve the materials hasn't been determined.

It is a major challenge and may be tough to accomplish, said Tim Farrar, president of consulting and research firm Telecom, Media & Finance Associates Inc. in Menlo Park, Calif.

Hauling back the precious cargo will be difficult, especially for a small company, Farrar said.

"It's a very complicated process, but at least it may drum up interest from the public to visit asteroids."